public interface Queue<E> {
    //入队
    public void enqueue(E e) throws Exception;

    //出队
    public E dequeue() throws Exception;

    //查看队首元素
    public E getFront() throws Exception;

    //查看队内元素数量
    public int getSize() throws Exception;

    //判断队内是否为空
    public boolean isEmpty() throws Exception;


}
